What happened
On 14 May 2019, a Bolkow Bo-209 Monsun 160RV, registration D-EFJG, performed a gear-up landing at Navan Airfield in Co. Meath. The aircraft, operated as a general aviation flight, was carrying two occupants—both of whom were pilots—on a short check flight following their recent purchase of the aircraft. After taking off from Runway 09 and completing one circuit of the airfield, the pilot attempted to land on the same runway. However, the nose landing gear had not been extended prior to touchdown. During the landing roll on the grass surface, the propeller blades and the lower engine cowling struck the ground. The impact caused substantial damage, including bending of the propeller blades and shock-loading of the engine. Both occupants exited the aircraft without injury, and no fire occurred.
The investigation
Investigators examined the aircraft's landing gear warning system and the cockpit procedures used during the approach. It was noted that the pilot had very limited experience on this specific aircraft type, having flown it only a few weeks prior. The investigation looked into the functionality of the amber warning light, which is designed to activate based on throttle position and airspeed. Post-occurrence testing revealed that the throttle-position switch was not activating the warning at the manufacturer-specified 1/3 throttle position, but rather much closer to the idle position. Additionally, the investigation found that the aircraft lacked an aural warning horn, a feature only present on later models of the Bo-209. The crew also reported that a piece of paper inside the checklist cover may have partially obscured the descent checklist items.
Findings
- The primary cause of the incident was that the nose landing gear was not extended before landing.
- The pilot's lack of operational familiarity with the Bolkow Bo-209 Monsun 160RV contributed to the error.
- The aircraft's landing gear warning system was less effective than specified, as the throttle-position switch activated much later in the approach than intended.
- The absence of an aural warning horn meant there was no audible alert to notify the pilot of the gear status.
- The layout of the 'FOR DESCENT' checklist and the potential obscuration of its text made it easier to miss the gear extension item.
- Environmental factors, such as a bumpy approach due to wind, may have served as a distraction.